Oracle Audio Technologies E10898-02 manual Setting the Guest’s Clock, Wallclock Time Skew Problems

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Mouse Pointer Tracking Problems

E.6 Setting the Guest’s Clock

Paravirtualized guests may perform their own system clock management, for example, using the NTPD (Network Time Protocol daemon), or the hypervisor may perform system clock management for all guests.

You can set paravirtualized guests to manage their own system clocks by setting the xen.independent_wallclock parameter to 1 in the /etc/sysctl.conf file. For example

"xen.independent_wallclock = 1"

If you want to set the hypervisor to manage paravirtualized guest system clocks, set xen.independent_wallclock to 0. Any attempts to set or modify the time in a guest will fail.

You can temporarily override the setting in the /proc file. For example

"echo 1 > /proc/sys/xen/independent_wallclock"

Note: This setting does not apply to hardware virtualized guests.

E.7 Wallclock Time Skew Problems

Oracle VM Release 2.1.1 introduces the use of the timer_mode parameter for hardware virtualized guests. This parameter, when properly applied, can reduce or even eliminate problems with wallclock time skew in most hardware virtualized guests. Wallclock time skew problems do not occur in paravirtualized guests.

Since the application of the correct value of the timer_mode parameter can be difficult to determine, you can pass the os-typeand os-variantcommand-line switches to virt-install to select the best timer_mode value for the guest operating system. When you use these virt-install parameters, the correct timer_mode value is automatically added to the guest configuration file. For example, to create an Oracle Enterprise Linux 5 64-bit guest, add the following to the virt-install command-line:

virt-install --hvm ... --os-type=linux --os-variant=el5_64 ...

For best results, additional parameters may be needed in the boot loader (grub.conf) configuration file for certain operating system variants after the guest is installed. Specifically, for optimal clock accuracy, Linux guest boot parameters should be specified to ensure that the pit clock source is utilized. Adding clock=pit nohpet nopmtimer for most guests will result in the selection of pit as the clock source for the guest. Published templates for Oracle VM will include these additional parameters.

Proper maintenance of virtual time can be tricky. The various parameters provide tuning for virtual time management and supplement, but do not replace, the need for an ntp time service running within guest. Ensure that the ntpd service is running and that the /etc/ntpd.conf configuration file is pointing to valid time servers.

E.8 Mouse Pointer Tracking Problems

If your mouse pointer fails to track your cursor in a VNC Viewer session in a hardware virtualized guest, add the following to the Oracle VM Server configuration file located at /etc/xen/xend-config.sxp to force the device model to use absolute (tablet) coordinates:

usbdevice='tablet'

Troubleshooting E-5

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Contents February E10898-02Page Contents Command-Line Tools Oracle VM Server Configuration File Page Preface Accessibility of Code Examples in DocumentationTTY Access to Oracle Support Services Command SyntaxConventions Page Why Virtualize? What is Virtualization?Introduction to Virtualization Oracle VM Xen TechnologyXen Technology Oracle VM Architecture shows the components of Oracle VM Oracle VM4Oracle VM Server User’s Guide Oracle VM Server Oracle VM ServerDomains, Guests and Virtual Machines HypervisorHypervisor Creating Virtual Machines Management DomainDomains Hardware Virtualization Vs. ParavirtualizationConfiguring Oracle VM Server Configuring Oracle VM ServerManaging Oracle VM Server Repositories Configuring Oracle VM Agent Oracle VM Agent Command-Line ToolOracle VM Agent Xmlrpc Configuring Oracle VM AgentDeploying Oracle VM Agent Starting Oracle VM AgentStopping Oracle VM Agent Monitoring Oracle VM AgentRemotely Starting a Guest with the Oracle VM Agent API Testing the Oracle VM Agent ConnectionDeleting a Guest with the Oracle VM Agent Oracle VM Agent UtilitiesRemotely Stopping a Guest with the Oracle VM Agent API Monitoring a Guest with the Oracle VM Agent6Oracle VM Server User’s Guide Supported Guest Operating Systems Creating a Guest-bit Hypervisor Supported Guest Operating Systems Supported Guest Operating SystemsEnabling Registration of Guests with Oracle VM Manager Creating a Guest Using a TemplateCreating a Guest Using a Template Mounting an ISOCreating a Guest Using virt-install Creating a Guest Using virt-installPress Enter Following question is displayed Would you like to enable graphics support yes or no? Creating the Root File System Creating a Paravirtualized Guest ManuallyCreating a Paravirtualized Guest Manually Populating the Root File System Configuring the GuestCreating a Hardware Virtualized Guest Manually Creating a Hardware Virtualized Guest ManuallyEdit /mnt/etc/sysconfig/network-scripts/ifcfg-eth0 Use VNCViewer to display the guest If you see this error message Restart the guest, using the xm command-line tool Installing Paravirtual Drivers Installing Paravirtual Drivers 16Oracle VM Server User’s Guide Using the xm Command-Line Interface Domain Monitoring and AdministrationDomain Lifecycle Monitoring Domains Using the xm Command-Line InterfaceViewing Host Information Using the xm Command-Line Interface 4Oracle VM Server User’s Guide Domain Live Migration Creating a Shared Virtual Disk Using OCFS2 on iSCSICreating a Shared Virtual Disk for Live Migration Delete entries that you do not want to use, for example Creating a Shared Virtual Disk for Live MigrationCreating a Shared Virtual Disk Using OCFS2 on SAN Adding a Shared Virtual Disk Using NFS Migrating a Domain Migrating a Domain6Oracle VM Server User’s Guide Repository Mount Options Repository Configuration FileManaging Oracle VM Server Repositories Oracle VM Server RepositoriesRemoving a Repository Adding a RepositoryOracle VM Server Repositories Command-Line Tools Restart ConfigureStart StopUUUID --uuid=UUID HelpNname --name=name RRAM --ram=RAMSdl Bvalue --bridge=valueVnc Vncport=portNoapic Os-variant=variantArch=arch Xargs --extra-args=args ParavirtLlocation --location=location Vif-type=typeHelp --long option Console domain-idDestroy domain-id Dmesg --clearMigrate domain-id host -l --live -r=MB --resource=MB =file --defconfig=fileList --long --label domain-id LogShutdown -a -w domain-id Restore statefileUnpause domain-id TopOracle VM Server Configuration File Loglevel Critical or Fatal Error Warn or Warning Info Debug Oracle VM Server Configuration FileLogfile location Xend-unix-xmlrpc-server yes no Xend-http-server yes noXend-unix-server yes no Xend-tcp-xmlrpc-server yes noXend-relocation-address IPAddress Xend-port portXend-relocation-port port Xend-address IPAddressExternal-migration-tool tool Enable-dump yes noDom0-min-mem memory Dom0-cpus CPUs6Oracle VM Server User’s Guide Configuration File Example Guest Configuration FilesConfiguration File Example Oracle VM Agent Architecture Oracle VM Agent ArchitectureOracle VM Agent Deployment Oracle VM Agent DeploymentOracle VM Agent Architecture D-3 4Oracle VM Server User’s Guide Debugging Tools TroubleshootingOracle VM Server Directories Using Dhcp Using DhcpGuest Console Access Oracle VM Server Command-Line ToolsGuest Console Access Cannot Display Graphical Installer When Creating Guests Cannot Display Graphical Installer When Creating GuestsHardware Virtualized Guest Console Not Displayed Mouse Pointer Tracking Problems Setting the Guest’s ClockWallclock Time Skew Problems Mouse Pointer Tracking ProblemsHardware Virtualized Guest Killed Hardware Virtualized Guest Windows InstallationHardware Virtualized Guest Killed Hardware Virtualized Guest Devices Not Working as ExpectedCD-ROM Image Not Found Firewall Blocks NFS AccessAttaching to a Console with the Grub Boot Loader TAP Disks with Paravirtualized Guests8Oracle VM Server User’s Guide Glossary Paravirtualized machine Oracle VM AgentOracle VM Server Oracle VM ManagerVirtual Machine VM Utility ServerVif Virtual diskGlossary-4 Index-1 IndexIndex-2
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